diff --git a/src/afs/LINUX/osi_compat.h b/src/afs/LINUX/osi_compat.h
index 808c608adf..bb4969ce87 100644
--- a/src/afs/LINUX/osi_compat.h
+++ b/src/afs/LINUX/osi_compat.h
@@ -534,7 +534,9 @@ afs_inode_setattr(struct osi_file *afile, struct iattr *newattrs) {
 
     int code = 0;
     struct inode *inode = OSIFILE_INODE(afile);
-#if defined(IOP_TAKES_USER_NAMESPACE)
+#if defined(IOP_TAKES_MNT_IDMAP)
+    code = inode->i_op->setattr(afs_mnt_idmap, afile->filp->f_dentry, newattrs);
+#elif defined(IOP_TAKES_USER_NAMESPACE)
     code = inode->i_op->setattr(afs_ns, afile->filp->f_dentry, newattrs);
 #elif !defined(HAVE_LINUX_INODE_SETATTR)
     code = inode->i_op->setattr(afile->filp->f_dentry, newattrs);
@@ -763,7 +765,9 @@ afs_d_path(struct dentry *dp, struct vfsmount *mnt, char *buf, int buflen)
 static inline int
 afs_setattr_prepare(struct dentry *dp, struct iattr *newattrs)
 {
-#if defined(IOP_TAKES_USER_NAMESPACE)
+#if defined(IOP_TAKES_MNT_IDMAP)
+    return setattr_prepare(afs_mnt_idmap, dp, newattrs);
+#elif defined(IOP_TAKES_USER_NAMESPACE)
     return setattr_prepare(afs_ns, dp, newattrs);
 #elif defined(HAVE_LINUX_SETATTR_PREPARE)
     return setattr_prepare(dp, newattrs);
diff --git a/src/afs/LINUX/osi_machdep.h b/src/afs/LINUX/osi_machdep.h
index 34940c60df..2220e05307 100644
--- a/src/afs/LINUX/osi_machdep.h
+++ b/src/afs/LINUX/osi_machdep.h
@@ -217,6 +217,10 @@ extern struct user_namespace *afs_ns;
 #  define afs_current_user_ns() ((struct user_namespace *)NULL)
 # endif
 
+#if defined(IOP_TAKES_MNT_IDMAP)
+extern struct mnt_idmap *afs_mnt_idmap;
+#endif
+
 static inline kuid_t afs_make_kuid(uid_t uid) {
     return make_kuid(afs_ns, uid);
 }
diff --git a/src/afs/LINUX/osi_module.c b/src/afs/LINUX/osi_module.c
index 79ba57c4da..fdc347d2c5 100644
--- a/src/afs/LINUX/osi_module.c
+++ b/src/afs/LINUX/osi_module.c
@@ -31,6 +31,10 @@
 #include <linux/sched.h>
 #include <linux/kernel.h>
 
+#if defined(IOP_TAKES_MNT_IDMAP)
+# include <linux/fs_struct.h>
+#endif
+
 #include "osi_pagecopy.h"
 
 extern struct file_system_type afs_fs_type;
@@ -46,6 +50,20 @@ int afs_global_owner = 0;
 struct user_namespace *afs_ns;
 #endif
 
+#if defined(IOP_TAKES_MNT_IDMAP)
+struct mnt_idmap *afs_mnt_idmap;
+
+static void
+afs_init_idmap(void)
+{
+    struct path fs_root;
+
+    get_fs_root(current->fs, &fs_root);
+    afs_mnt_idmap = mnt_idmap(fs_root.mnt);
+    path_put(&fs_root);
+}
+#endif
+
 int __init
 afs_init(void)
 {
@@ -55,6 +73,10 @@ afs_init(void)
     afs_ns = afs_current_user_ns();
 #endif
 
+#if defined(IOP_TAKES_MNT_IDMAP)
+    afs_init_idmap();
+#endif
+
     osi_Init();
 
     /* Initialize CellLRU since it is used while traversing CellServDB proc
diff --git a/src/afs/LINUX/osi_vnodeops.c b/src/afs/LINUX/osi_vnodeops.c
index d875788b62..2c5439dfd0 100644
--- a/src/afs/LINUX/osi_vnodeops.c
+++ b/src/afs/LINUX/osi_vnodeops.c
@@ -1146,7 +1146,10 @@ vattr2inode(struct inode *ip, struct vattr *vp)
  * Linux version of setattr call. What to change is in the iattr struct.
  * We need to set bits in both the Linux inode as well as the vcache.
  */
-#if defined(IOP_TAKES_USER_NAMESPACE)
+#if defined(IOP_TAKES_MNT_IDMAP)
+static int
+afs_notify_change(struct mnt_idmap *idmap, struct dentry *dp, struct iattr *iattrp)
+#elif defined(IOP_TAKES_USER_NAMESPACE)
 static int
 afs_notify_change(struct user_namespace *mnt_userns, struct dentry *dp, struct iattr *iattrp)
 #else
@@ -1180,7 +1183,18 @@ out:
     return afs_convert_code(code);
 }
 
-#if defined(IOP_TAKES_USER_NAMESPACE)
+#if defined(IOP_TAKES_MNT_IDMAP)
+static int
+afs_linux_getattr(struct mnt_idmap *idmap, const struct path *path, struct kstat *stat,
+		  u32 request_mask, unsigned int sync_mode)
+{
+	int err = afs_linux_revalidate(path->dentry);
+	if (!err) {
+		generic_fillattr(afs_mnt_idmap, path->dentry->d_inode, stat);
+	}
+	return err;
+}
+#elif defined(IOP_TAKES_USER_NAMESPACE)
 static int
 afs_linux_getattr(struct user_namespace *mnt_userns, const struct path *path, struct kstat *stat,
 		  u32 request_mask, unsigned int sync_mode)
@@ -1661,7 +1675,11 @@ struct dentry_operations afs_dentry_operations = {
  * name is in kernel space at this point.
  */
 
-#if defined(IOP_TAKES_USER_NAMESPACE)
+#if defined(IOP_TAKES_MNT_IDMAP)
+static int
+afs_linux_create(struct mnt_idmap *idmap, struct inode *dip,
+		 struct dentry *dp, umode_t mode, bool excl)
+#elif defined(IOP_TAKES_USER_NAMESPACE)
 static int
 afs_linux_create(struct user_namespace *mnt_userns, struct inode *dip,
 		 struct dentry *dp, umode_t mode, bool excl)
@@ -1953,7 +1971,11 @@ afs_linux_unlink(struct inode *dip, struct dentry *dp)
 }
 
 
-#if defined(IOP_TAKES_USER_NAMESPACE)
+#if defined(IOP_TAKES_MNT_IDMAP)
+static int
+afs_linux_symlink(struct mnt_idmap *idmap, struct inode *dip,
+		  struct dentry *dp, const char *target)
+#elif defined(IOP_TAKES_USER_NAMESPACE)
 static int
 afs_linux_symlink(struct user_namespace *mnt_userns, struct inode *dip,
 		  struct dentry *dp, const char *target)
@@ -1988,7 +2010,11 @@ out:
     return afs_convert_code(code);
 }
 
-#if defined(IOP_TAKES_USER_NAMESPACE)
+#if defined(IOP_TAKES_MNT_IDMAP)
+static int
+afs_linux_mkdir(struct mnt_idmap *idmap, struct inode *dip,
+		struct dentry *dp, umode_t mode)
+#elif defined(IOP_TAKES_USER_NAMESPACE)
 static int
 afs_linux_mkdir(struct user_namespace *mnt_userns, struct inode *dip,
 		struct dentry *dp, umode_t mode)
@@ -2068,7 +2094,13 @@ afs_linux_rmdir(struct inode *dip, struct dentry *dp)
 }
 
 
-#if defined(IOP_TAKES_USER_NAMESPACE)
+#if defined(IOP_TAKES_MNT_IDMAP)
+static int
+afs_linux_rename(struct mnt_idmap *idmap,
+		 struct inode *oldip, struct dentry *olddp,
+		 struct inode *newip, struct dentry *newdp,
+		 unsigned int flags)
+#elif defined(IOP_TAKES_USER_NAMESPACE)
 static int
 afs_linux_rename(struct user_namespace *mnt_userns,
 		 struct inode *oldip, struct dentry *olddp,
@@ -2092,7 +2124,7 @@ afs_linux_rename(struct inode *oldip, struct dentry *olddp,
     struct dentry *rehash = NULL;
 
 #if defined(HAVE_LINUX_INODE_OPERATIONS_RENAME_TAKES_FLAGS) || \
-    defined(IOP_TAKES_USER_NAMESPACE)
+    defined(IOP_TAKES_MNT_IDMAP) || defined(IOP_TAKES_USER_NAMESPACE)
     if (flags)
 	return -EINVAL;		/* no support for new flags yet */
 #endif
@@ -3388,7 +3420,10 @@ done:
  * Check access rights - returns error if can't check or permission denied.
  */
 
-#if defined(IOP_TAKES_USER_NAMESPACE)
+#if defined(IOP_TAKES_MNT_IDMAP)
+static int
+afs_linux_permission(struct mnt_idmap *idmap, struct inode *ip, int mode)
+#elif defined(IOP_TAKES_USER_NAMESPACE)
 static int
 afs_linux_permission(struct user_namespace *mnt_userns, struct inode *ip, int mode)
 #elif defined(IOP_PERMISSION_TAKES_FLAGS)
diff --git a/src/cf/linux-kernel-sig.m4 b/src/cf/linux-kernel-sig.m4
index e0cc9a2f38..5301f35036 100644
--- a/src/cf/linux-kernel-sig.m4
+++ b/src/cf/linux-kernel-sig.m4
@@ -28,4 +28,17 @@ dnl define.
 AS_IF([test AS_VAR_GET([ac_cv_linux_operation_inode_operations_create_user_namespace]) = yes],
       [AC_DEFINE([IOP_TAKES_USER_NAMESPACE], 1,
                  [define if inodeops require struct user_namespace])])
+dnl Linux 6.3 replaced the user_namespace parameter with mnt_idmap for
+dnl the inode operations functions.
+AC_CHECK_LINUX_OPERATION([inode_operations], [create], [mnt_idmap],
+                         [#include <linux/fs.h>],
+                         [int],
+                         [struct mnt_idmap *idmap,
+                         struct inode *inode, struct dentry *dentry,
+                         umode_t umode, bool flag])
+dnl if HAVE_LINUX_INODE_OPERATIONS_CREATE_MNT_IDMAP, create a more generic
+dnl define.
+AS_IF([test AS_VAR_GET([ac_cv_linux_operation_inode_operations_create_mnt_idmap]) = yes],
+      [AC_DEFINE([IOP_TAKES_MNT_IDMAP], 1,
+                 [define if inodeops require struct mnt_idmap])])
 ])
\ No newline at end of file